Sen. Joe Lieberman (I-Conn.) said Thursday he’s open to supporting Republican Linda McMahon over Democrat Richard Blumenthal in his state’s Senate race, a move that would land him in hot water with Democrats back home and in Washington.

“I said I’m open,” Lieberman told POLITICO. “Is it theoretically possible? Yes. I probably know Blumenthal better, but I know Linda McMahon — she was on the state board of higher education, and I met with her a couple of times in that capacity. This is the great privilege that voters of Connecticut gave me in 2006 as an independent. Wait and see.”

Asked whether he’s concerned about a backlash from the Democratic Party if he supports McMahon, he said: “I’m just saying I’m not eliminating it as a possibility.” Lieberman said he was undecided on which party’s candidate to support in the Connecticut gubernatorial race as well.

A Lieberman aide said the senator was simply repeating what he had said previously — that he’s undecided whether to get into the race and, for the moment, is not endorsing anyone.

But if and when Lieberman does decide whom to back in the Connecticut Senate race, it’ll be a window into whether he believes he’s better off ingratiating himself with right-leaning voters in his state or shoring up his support in the Democratic Party ahead of 2012, when he’s up for reelection.

“He’s an independent — what do you expect him to say?” Reid told reporters.

Asked if he’d be upset if Lieberman endorsed McMahon, Reid said: “I doubt he will do that, but it’s up to him.”

Lieberman’s relationship with the Democratic Party has become increasingly frosty since he was chosen in 2000 to run with Al Gore in the presidential race. In 2004, he sought the Democratic nomination for president but lost in the primary amid opposition from liberals for his hawkish stance on the Iraq war.

In 2006, Lieberman failed to quell a liberal rebellion against his Senate candidacy, losing the primary to Democratic businessman Ned Lamont. Lieberman then bucked the base and went on to win reelection as an independent.

He later agreed to caucus with Democrats in 2007, allowing them to retain a 51-49 majority in the Senate — and Democrats gave him the Homeland Security Committee chairmanship.

But Lieberman became even more of a pariah on the left for actively supporting GOP Sen. John McCain’s presidential bid in 2008 and for criticizing then-candidate Barack Obama in a speech at the Republican National Convention. And while he ended up supporting the Democratic health care law, his resistance to a public insurance option angered many Democrats last winter.

In January, Lieberman declined to say whether he’d endorse McMahon because she supported him in the 2006 race and Blumenthal supported Lamont.

“She was good enough to support me financially and politically in the 2006 general election,” Lieberman said to a local television station. “But as I say, these are important jobs at a tough time — a U.S. senator, a governor — so I’m going to watch these for a while and enjoy watching it.”

Before Sen. Chris Dodd (D-Conn.) announced he’d retire at the end of the year, Blumenthal was seriously considering challenging Lieberman in 2012. Instead, he’s mired in a battle with McMahon, former CEO of World Wrestling Entertainment. And a new Quinnipiac poll found Blumenthal leading her by a whopping 25 points, despite the Democratic attorney general’s recently reported misstatements about his service during the Vietnam War.

Asked about Blumenthal’s statements about Vietnam, Lieberman said he was “surprised” but noted that the Democrat apologized for them.

“In the end, Dick Blumenthal will be judged on his overall record, as everyone else will,” Lieberman said. “Ultimately, he apologized and said he made a mistake and said he really regrets it.”

Lieberman also noted he could support a third-party candidate as well in the Senate race.